Arnaud Spiwack
@aspiwack.bsky.social
Multi-classed Software Engineer/Constructive Mathematician. Sometimes plays video games sort of fast. Puts topoi in your computer.
Pinned
Arnaud Spiwack
@aspiwack.bsky.social
· Nov 17
👋 Welcome (numerous) newcomers.
I'm a Tokyo-based, French, polyglot software engineer, computer scientist, mathematician, and hobbyist speedrunner.
I generally speak of programming languages and their theory, linguistics, science, video games, movies, books. And how the world is very funny indeed.
I'm a Tokyo-based, French, polyglot software engineer, computer scientist, mathematician, and hobbyist speedrunner.
I generally speak of programming languages and their theory, linguistics, science, video games, movies, books. And how the world is very funny indeed.
Reposted by Arnaud Spiwack
In one of his texts, Douglas Hofstadter suggests publishing a book called “Reviews of this Book” (you would first ask various reviewers to review the concept and collect their reviews into a book, then send them the result so they can update their reviews, and so on until a fixed point is reached).
November 30, 2025 at 9:19 AM
In one of his texts, Douglas Hofstadter suggests publishing a book called “Reviews of this Book” (you would first ask various reviewers to review the concept and collect their reviews into a book, then send them the result so they can update their reviews, and so on until a fixed point is reached).
Reposted by Arnaud Spiwack
I…
November 26, 2025 at 7:40 PM
I…
Et fin Janvier aux JFLAs que c'est en endroit bien!
Ah oui j'oubliais. Si vous avez raté Véronique à Grenoble vous pouvez assister à son exposé à Paris campus de Jussieu
www.lip6.fr/colloquium/
Quelle tournée triomphale !
www.lip6.fr/colloquium/
Quelle tournée triomphale !
November 26, 2025 at 10:36 PM
Et fin Janvier aux JFLAs que c'est en endroit bien!
Reposted by Arnaud Spiwack
Recent discussion about the perils of doors in gamedev reminded me of a bug caused by a door in a game you may have heard of called "Half Life 2".
I wrote it up over on Mastodon (I find it's better at long threads):
mastodon.gamedev.place/@TomF/115589...
I wrote it up over on Mastodon (I find it's better at long threads):
mastodon.gamedev.place/@TomF/115589...
Tom Forsyth (@[email protected])
Attached: 1 image
Recent discussion about the perils of doors in gamedev reminded me of a bug caused by a door in a game you may heard of called "Half Life 2". Are you sitting comfortably? Then I sha...
mastodon.gamedev.place
November 21, 2025 at 10:00 PM
Recent discussion about the perils of doors in gamedev reminded me of a bug caused by a door in a game you may have heard of called "Half Life 2".
I wrote it up over on Mastodon (I find it's better at long threads):
mastodon.gamedev.place/@TomF/115589...
I wrote it up over on Mastodon (I find it's better at long threads):
mastodon.gamedev.place/@TomF/115589...
Nice stuff.
In differential testing, some operations may have to make a choice between several valid options. But what if you make a different choice than the reference implementation?
François Pottier shows how to handle this with his Monolith library cambium.inria.fr/blog/testing...
In differential testing, some operations may have to make a choice between several valid options. But what if you make a different choice than the reference implementation?
François Pottier shows how to handle this with his Monolith library cambium.inria.fr/blog/testing...
Gagallium : Testing a priority queue with Monolith
A priority queue is a data structure whose specification is non-deterministic: indeed, if a priority queue contains several key-value pairs whose key is minimal, then any such pair can be legally…
cambium.inria.fr
November 25, 2025 at 12:50 AM
Nice stuff.
In differential testing, some operations may have to make a choice between several valid options. But what if you make a different choice than the reference implementation?
François Pottier shows how to handle this with his Monolith library cambium.inria.fr/blog/testing...
In differential testing, some operations may have to make a choice between several valid options. But what if you make a different choice than the reference implementation?
François Pottier shows how to handle this with his Monolith library cambium.inria.fr/blog/testing...
Now that I live in Japan, I can claim with confidence that French TGV is the most amazing train in the world. Which is what Canada appears to be investing in 👍.
Japanese Shinkansen is, on the other hand, the best train *network* in the world. Their frequency is mind-boggling.
Japanese Shinkansen is, on the other hand, the best train *network* in the world. Their frequency is mind-boggling.
Canada to accelerate high-speed rail project connecting Quebec City and Toronto
“Canada’s largest infrastructure project ever will connect nearly 20 million Canadians between Quebec City and Toronto with 300km/hour high-speed rail.”
“Canada’s largest infrastructure project ever will connect nearly 20 million Canadians between Quebec City and Toronto with 300km/hour high-speed rail.”
Canada to accelerate high-speed rail project connecting Quebec City and Toronto
With the passing of the budget, the Government of Canada will fast-track the Alto high-speed rail project to connect Quebec City and Toronto.
cultmtl.com
November 24, 2025 at 1:19 AM
Now that I live in Japan, I can claim with confidence that French TGV is the most amazing train in the world. Which is what Canada appears to be investing in 👍.
Japanese Shinkansen is, on the other hand, the best train *network* in the world. Their frequency is mind-boggling.
Japanese Shinkansen is, on the other hand, the best train *network* in the world. Their frequency is mind-boggling.
When an impossibly large space meets a ludicrously long time…
It's Friday, and apparently bluesky is ready for this fun revelation:
Dinosaurs lived on the other side the Galaxy.
Dinosaurs lived on the other side the Galaxy.
November 22, 2025 at 11:25 PM
When an impossibly large space meets a ludicrously long time…
En Japonais, les poivrons rouge c'est aka paprika (赤パプリカ).
Mon cerveau à chaque fois: attention les secousses.
Mon cerveau à chaque fois: attention les secousses.
November 22, 2025 at 9:00 AM
En Japonais, les poivrons rouge c'est aka paprika (赤パプリカ).
Mon cerveau à chaque fois: attention les secousses.
Mon cerveau à chaque fois: attention les secousses.
Part of this is me experimenting with form. What I really meant to say was: this is a magnificent sentence of masterful word crafting (I do love me a magnificent sentence of masterful word crafting). Does it come across?
I was afraid that adding context would lessen the sentence itself. Would it?
I was afraid that adding context would lessen the sentence itself. Would it?
“You would […] stop being biology and start being physics”.
www.youtube.com/watch?v=qu8n...
www.youtube.com/watch?v=qu8n...
What if ALL the sun’s power was focused in one place?
Get a copy of What If? 2 and Randall’s other books at: https://xkcd.com/books
More serious answers to absurd questions at: https://what-if.xkcd.com/
This question comes from Max, who asks: What if…
www.youtube.com
November 20, 2025 at 8:19 AM
Part of this is me experimenting with form. What I really meant to say was: this is a magnificent sentence of masterful word crafting (I do love me a magnificent sentence of masterful word crafting). Does it come across?
I was afraid that adding context would lessen the sentence itself. Would it?
I was afraid that adding context would lessen the sentence itself. Would it?
“You would […] stop being biology and start being physics”.
www.youtube.com/watch?v=qu8n...
www.youtube.com/watch?v=qu8n...
What if ALL the sun’s power was focused in one place?
Get a copy of What If? 2 and Randall’s other books at: https://xkcd.com/books
More serious answers to absurd questions at: https://what-if.xkcd.com/
This question comes from Max, who asks: What if…
www.youtube.com
November 19, 2025 at 2:53 PM
“You would […] stop being biology and start being physics”.
www.youtube.com/watch?v=qu8n...
www.youtube.com/watch?v=qu8n...
It's been a while. I'll be streaming this week's Final Fantasy VI: Worlds Collide seed of the week. It's all about finding Celes.
Stream starts at 00.30 UTC twitch.tv/notnotarnaud
Stream starts at 00.30 UTC twitch.tv/notnotarnaud
Twitch
Twitch is the world's leading video platform and community for gamers.
twitch.tv
November 19, 2025 at 12:20 AM
It's been a while. I'll be streaming this week's Final Fantasy VI: Worlds Collide seed of the week. It's all about finding Celes.
Stream starts at 00.30 UTC twitch.tv/notnotarnaud
Stream starts at 00.30 UTC twitch.tv/notnotarnaud
I agree with everything in this. Though not a lot of these actions can be done locally.
And, of course, use @softwareheritage.org .
Archive your research software, and archive your articles' source.
And, of course, use @softwareheritage.org .
Archive your research software, and archive your articles' source.
These very nice slides by Marie Farge on how researchers can regain control of publication have been brought to my attention: openscience.ens.fr/MARIE_FARGE/... — I think they're worth spreading more widely!
November 18, 2025 at 12:07 AM
I agree with everything in this. Though not a lot of these actions can be done locally.
And, of course, use @softwareheritage.org .
Archive your research software, and archive your articles' source.
And, of course, use @softwareheritage.org .
Archive your research software, and archive your articles' source.
I hope this is true.
November 17, 2025 at 12:42 AM
I hope this is true.
This is a list of excellent one-panel comics (all in English, you don't need to read French to appreciate). Even though I must (slightly shamefully perhaps) admit to not understand this first one.
Je déclare ouverte ma liste personnelle de one-panel-comics préférés.
Pour marquer sa subjectivité elle commencera par la Joconde des one-panel, à savoir "Cow Tools", par Gary Larson.
Pour marquer sa subjectivité elle commencera par la Joconde des one-panel, à savoir "Cow Tools", par Gary Larson.
November 17, 2025 at 12:23 AM
This is a list of excellent one-panel comics (all in English, you don't need to read French to appreciate). Even though I must (slightly shamefully perhaps) admit to not understand this first one.
The King and the Mockingbird is one of my favourite movies. A pioneer of the genre (its official release date is 1980, but a version was made in 1953 already). It's not very well known by the general public was incredibly influential with e.g. the likes of Ghibli's Miyazaki citing it as inspiration.
Le Roi et L'Oiseau
A delightful animation that dares to ask the bold questions, like "what if OSHA didn't exist?"
m.imdb.com/fr/title/tt0...
A delightful animation that dares to ask the bold questions, like "what if OSHA didn't exist?"
m.imdb.com/fr/title/tt0...
Le roi et l'oiseau (1980) ⭐ 7.7 | Animation, Famille, Fantastique
1h 23m | Tous publics
m.imdb.com
November 16, 2025 at 1:43 AM
The King and the Mockingbird is one of my favourite movies. A pioneer of the genre (its official release date is 1980, but a version was made in 1953 already). It's not very well known by the general public was incredibly influential with e.g. the likes of Ghibli's Miyazaki citing it as inspiration.
Je reçois un email dont l'intitulé commence par « Servir la science ». Et je me dis que la génération qui n'a jamais lu Léonard est maintenant assez grande pour envoyer des emails professionnels.
November 12, 2025 at 12:03 PM
Je reçois un email dont l'intitulé commence par « Servir la science ». Et je me dis que la génération qui n'a jamais lu Léonard est maintenant assez grande pour envoyer des emails professionnels.
In Tokyo, people typically set the height of their bicycle saddle so that they can comfortably put both feet on the ground. Optimising for the inevitable stop at the cost of speed. In a urban environment this is probably best. Though it may explain why so many bicycles here are electric.
November 12, 2025 at 7:12 AM
In Tokyo, people typically set the height of their bicycle saddle so that they can comfortably put both feet on the ground. Optimising for the inevitable stop at the cost of speed. In a urban environment this is probably best. Though it may explain why so many bicycles here are electric.
@kmett.ai quick question: did you realise, when you designed the Divisible class that an equivalent presentation could have been
divide' :: f a -> f a -> f a
conquer :: f a
If so, why did you prefer the presentation with
divide :: (a -> (b, c)) -> f b -> f c -> f a
?
divide' :: f a -> f a -> f a
conquer :: f a
If so, why did you prefer the presentation with
divide :: (a -> (b, c)) -> f b -> f c -> f a
?
November 11, 2025 at 8:17 AM
@kmett.ai quick question: did you realise, when you designed the Divisible class that an equivalent presentation could have been
divide' :: f a -> f a -> f a
conquer :: f a
If so, why did you prefer the presentation with
divide :: (a -> (b, c)) -> f b -> f c -> f a
?
divide' :: f a -> f a -> f a
conquer :: f a
If so, why did you prefer the presentation with
divide :: (a -> (b, c)) -> f b -> f c -> f a
?
Reposted by Arnaud Spiwack
I thought the notion of “sheaf for a Lawvere-Tierney topology” was a very complicated one, but I realized it's actually not so complicated, and it can be defined completely internally (i.e., you don't need to know what a topos is, just how constructive math works). •1/7
November 9, 2025 at 10:18 AM
I thought the notion of “sheaf for a Lawvere-Tierney topology” was a very complicated one, but I realized it's actually not so complicated, and it can be defined completely internally (i.e., you don't need to know what a topos is, just how constructive math works). •1/7
In fact, isn't a tail call technically have a function call?
Mmm 🤔 Is half a function application like half an A press?
November 8, 2025 at 12:51 AM
In fact, isn't a tail call technically have a function call?
An intriguing thing about Wasm is its treatment of control structures. Wasm proposes more structured than gotos, but less so that loops: lexical labels.
The idea is that labels are scoped, and jump instructions can only jump to an in-scope label. 1/3
The idea is that labels are scoped, and jump instructions can only jump to an in-scope label. 1/3
November 5, 2025 at 12:44 AM
An intriguing thing about Wasm is its treatment of control structures. Wasm proposes more structured than gotos, but less so that loops: lexical labels.
The idea is that labels are scoped, and jump instructions can only jump to an in-scope label. 1/3
The idea is that labels are scoped, and jump instructions can only jump to an in-scope label. 1/3
It was just an itemize environment with just text (no maths) in it. So nothing advanced. It still caught my eye. Done, appropriately, by a scientist. Though I am amused at the idea that Latex is one of the things that survived an apocalypse.
This must be how long it takes for inspiration to percolate.
On other news, Fire Force is the first time I saw someone typing some Latex in an anime. Tip of my hat to that. You win, Fire Force.
On other news, Fire Force is the first time I saw someone typing some Latex in an anime. Tip of my hat to that. You win, Fire Force.
November 2, 2025 at 11:54 PM
It was just an itemize environment with just text (no maths) in it. So nothing advanced. It still caught my eye. Done, appropriately, by a scientist. Though I am amused at the idea that Latex is one of the things that survived an apocalypse.
Kaiju #8 and Fire Force are two animés that I watched recently (and quite liked) which remind me, for different reasons, of Attack on Titan. They were started in 2020 and 2019 respectively. Attack on titan in 2009. By the time the anime started in 2013, its popularity was well established, I think.
November 1, 2025 at 12:55 PM
Kaiju #8 and Fire Force are two animés that I watched recently (and quite liked) which remind me, for different reasons, of Attack on Titan. They were started in 2020 and 2019 respectively. Attack on titan in 2009. By the time the anime started in 2013, its popularity was well established, I think.
Reposted by Arnaud Spiwack
things you can curry :
- dishes
- favors
- horses
- people
- software functions
- dishes
- favors
- horses
- people
- software functions
October 18, 2025 at 3:28 PM
things you can curry :
- dishes
- favors
- horses
- people
- software functions
- dishes
- favors
- horses
- people
- software functions
Reposted by Arnaud Spiwack
